NEW YORK (TheStreet) -- The CEOS of Apple (AAPL), Twitter (TWTR) and Virgin (VA) have all demonstrated their unusual leadership gifts in recent weeks, according to Dr. Bill Boulding, dean of Duke University's Fuqua School of Business.

Apple's Tim Cook recently presided over the much-anticipated Apple Worldwide Developers Conference. "The big thing about Tim is that he is so authentic," said Boulding. "What Tim believes in so deeply is that collaboration is the key to innovation, and he has built an organization that is unbelievably collaborative and as a consequence also unbelievably innovative."

Meantime at Twitter, the focus is on a transition of leadership now that CEO Dick Costolo has decided to step down. Boulding said Costolo's departure is "a great example of something that I think is very, very important in all leaders, which is this level of humility and a recognition that leadership isn't about self-interest and selfishness, but rather it's about making people around you successful and making sure that the organization thrives."

Boulding added that Costolo believes that unlocking the value of Twitter may require a new leader.

At Virgin, CEO Richard Branson recently announced that he would offer up to a year of paid parental leave (both for moms and dads) for some employees. Boulding called the move an example of forward-thinking leadership.

"What he has done is recognize that family leave is something we shouldn't think of as being gender specific" Boulding said. "So he's gotten an enormous amount of publicity in doing this. It's probably an experiment on his part, because it's not across-the-board within his company, and so I think he's doing something that's really exciting to see."

Boulding added that he is optimistic about the leadership at publicly traded companies. "We're seeing the successful model in business is the model where the CEOs, the business leaders support the ambitions of others," he said. He added that those leaders also "create an organization where they themselves are authentic, that the draw out the authenticity from others, and they embrace the idea that the way they're going to drive innovation and create value is by embracing people who are different from themselves."